Metabolic changes during cold water immersion.

This study was conducted in order to compare the metabolic responses of individuals exposed to long duration cold water immersion under two experimental conditions: 1) Heat loss compensated by shivering thermogenesis, and 2) heat loss compensated by intermittent periods of exercise. Nine subjects participated in two experimental trials 1) Subjects wearing insulated survival suits who did perform mild leg cycling during immersion 2) Subjects wearing insulated survival suits who did not perform exercise. Blood was sampled pre- and postimmersion. Blood was assayed for free fatty acids (FFA), lactate, creatine kinase and glucose. Intermittent periods of physical activity during cold water immersion resulted in a higher increase in FFA than during inactivity. In lactate, glucose, and creatine kinase there were no significant differences between the changes from pre- to postimmersion under the two conditions.